Electrostatic Substrate Fixing Device with Protrusions for Uniform Temperature
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Solution Overview
Problem
Conventional substrate fixing devices, such as electrostatic chucks, face challenges in maintaining uniform temperature and impedance during plasma processing due to wear issues and non-uniform thermal conductivity, leading to non-uniform substrate processing.
Innovation Solution
A substrate fixing device with a lower electrode, dielectric layer, and protrusions featuring an insulating layer and a hard upper layer, along with a porous layer and helium gas, is designed to minimize wear and enhance thermal conductivity for uniform temperature distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical chuck is used to fix the substrate, then the substrate can be held in place, but wear occurs leading to reduced durability and non-uniform temperature distribution
Solution Approach 1:
The patent replaces the mechanical contact-based chuck system with an electrostatic field-based fixing system. The lower electrode generates an electrostatic field that holds the substrate without mechanical contact, eliminating wear from friction and mechanical stress. This substitution of mechanical interaction with electromagnetic interaction resolves the durability issue while maintaining substrate fixation capability.
Solution Approach 2:
The dielectric layer serves as an intermediary between the lower electrode and the substrate. It enables electrostatic fixation while providing thermal insulation and preventing direct contact that would cause wear. The dielectric layer mediates the interaction between the electrode and substrate, allowing force transmission without mechanical wear.
2Temperature
If conventional electrostatic chucks are used, then substrate fixation is achieved, but non-uniform thermal conductivity leads to non-uniform temperature distribution
Solution Approach 1:
The patent introduces protrusions with insulating layers at specific locations on the dielectric layer surface. These localized structures create regions of different thermal conductivity - the protrusions provide electrical contact points while the insulating layers maintain thermal isolation. This local differentiation of properties enables uniform temperature distribution by preventing thermal short-circuits while maintaining electrostatic fixation.
Solution Approach 2:
The protrusions are constructed as composite structures with insulating layers made of different materials (e.g., silicon oxide, nitrogen oxide) with varying thermal conductivities. This composite approach allows optimization of both electrical and thermal properties - the insulating layers provide electrical isolation while their specific thermal conductivity values are selected to achieve uniform heat distribution across the substrate surface.
3Force
If the dielectric layer directly contacts the substrate, then electrostatic fixation works, but wear and material transfer occur reducing durability
Solution Approach 1:
The patent replaces direct mechanical contact between the dielectric layer and substrate with field-based interaction. The electrostatic field extends through the dielectric layer to hold the substrate without physical contact at the contact points, eliminating wear mechanisms associated with friction and adhesion. The holding force is maintained through electromagnetic interaction rather than mechanical bonding.
Solution Approach 2:
The insulating layers on the protrusions serve as a protective cushion between the dielectric layer and substrate. These layers are designed beforehand to prevent direct contact and potential damage, providing a buffer that absorbs mechanical stresses and prevents material transfer while allowing electrostatic forces to act through the insulating barrier.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution increases the durability and uniformity of temperature distribution across the substrate, reducing thermal conductivity variations and maintaining stable impedance, thereby ensuring uniform plasma processing.
Implementation Method 1
an electrostatic chuck which fixes the substrate with an electrostatic force
Implementation Method 2
The dielectric layer is disposed on the lower electrode. The protrusions are spaced apart from each other, and are protruded from the dielectric layer. Each protrusion includes an insulating layer disposed on the dielectric layer
Implementation Method 3
the substrate fixing device may further include helium gas charged between adjacent protrusions
Data Source
AI summary
In a substrate fixing device and a method form manufacturing the substrate fixing device, the substrate fixing device includes a lower electrode, a dielectric layer and a plurality of protrusions. The dielectric layer is disposed on the lower electrode. The protrusions are spaced apart from each other, and are protruded from the dielectric layer. Each of the protrusions includes an insulating layer disposed on the dielectric layer, and an upper layer disposed on the insulating layer and contacting a substrate.